Appendix. 



63 



Investigation of alizarin of madder — Schunck 1848 



of anthracene Anderson 1862 



of the quinones Grsebe 1868 



Formation of anthracene from alizarin, Graebe and Lieber- 



man 1868 



of alizarin from anthracene, Graebe and Lieber- 



man 1869 



Purpurtn, the less important color compound of madder, 

 having the ultimate composition of trioxyanthraquinone, is this 

 year reported to be synthesized from alizarin. ^^ 



A ton of alizarin is saved from about 2,000 tons of coal or 

 160 tons of coal tar. By this saving, large agricultural districts 

 in Holland and Alsace and in Asia Minor, employed hitherto in 

 producing color, can be devoted to the production of food. 



The production of salicylic acid from phenol, through action 

 of carbonic anhydride, is simply a direct synthesis : a molecule 

 of carboxyl (CO3H) being substituted for one of the hydrogen 

 atoms of phenol. That is, the elements of a molecule of car- 

 bonic acid gas, COg, are added to the elements of a molecule of 

 phenol, CgHgO, to form a molecule of salicylic acid, C^HgOg. 

 H 



C 



H— C C— 



H 



I II 



H-C C- 



'^ / 

 C 



I 

 OH 



Phenol, CgHgO. 



H 



^ JOH 



Salicylic acid, C^HgOc 



(23) Lalande: Oompt. Rend; Ixxlx, 669; in Jour. Chem. 80c., 1875, 69. 

 Rosentiehl: Compt. Rend., \xxix,7Qi; in Jour. Chem. Soc, 1874,373. 



5 



